Japan gets big quake alert, but only minor shake

Japan’s Meteorological Agency says it is investigating after it issued an alert for a very strong earthquake that turned out to be only a mild shake.

Loud alarms rang from cellphones and TVs just before 5 p.m. Japan time on Thursday, warning of an earthquake of magnitude 7.8, which could cause severe damage. It said residents throughout Japan should be prepared for a jolt.

A few minutes later the Meteorological Agency reported a magnitude 2.3 quake cantered in Wakayama prefecture, in western Japan. Under the Japanese system for measuring quakes, it barely registered.